If you are shooting a true HW rifle and not the Beeman then I have a hint for you. Although HW and Beeman are of the same design, the barrels are drastically different......so I speak only of mainly the HW95 or HW80.
This is a set of expensive pellets, however it has been my experience that using them allows me to shoot sugar cubes at 50 yards and on average get three out of five and on a good day when I am relaxed and not distracted 5/8 inch groups. All other pellets will be from 1.5 to 2 inches except the Hades that is very accurate for a lead pellet, however it is so slow the shot curve is extreme.
So I use two No Lead pellets, the 11.75 GTO and the 12.96 Barracuda Green. In my tuned HW95 with the Vortex 4 steel both of these pellets exceed 800 fps and the Barracuda Green also puts out 19 fpe at the muzzle, but mainly these are two very accurate pellets in almost any HW rifle. They are not cheap, and cost around 30 bucks for a tin of 200. Some of my match .22 rimfire are a couple pennies cheaper.
I also shoot with only the forearm rested , and I can tell with age that the ability to hold a rifle steady and still is hit or miss, some days I can, some I know in a shot or two , not today!!
Any way try the GTO and the Barracuda Green, In my 95 the GTO is 860 plus fps, and I forget what the Barracuda Green is.
Be careful with these pellets, they will depending on what you shoot, sometimes bounce right back at you.
That feller Steve somebody?? The one who used to review lots of guns and conduct the give away on this site did a review of the HW 95 and he found also that the GTO was his best pellet . That review is on Youtube if you care to do a quick search for it.
Cheers
Kit